With the advancement of science and technology and the improvement of living standard, the constant temperature valve cores have been widely used in each kind of water supply system for bath in household and hotel, etc. The users can adjust the outlet water temperature according to actual demands by the valve cores, and after presetting temperature, the mixed outlet water temperature will be constant, thus, the problem of sometimes hot and sometimes cold water due to change of inlet water pressure and temperature by common valve core can be solved, and the valve core is safe and prevent user's scald.
The key points of effectively keeping the outlet water temperature constant are to sense and measure true and effective the outlet water temperature, and to sensitively adjust the proportion of cold and hot inlet water. Sensing and measuring true and effective outlet water temperature means to fully mix cold and hot water, sense and measure the temperature of the outlet mixed water, which can be completely achieved with prior art;
In addition, the controlling the inlet water pressure balance is also a critical factor that ensures the outlet water temperature constant. The majority of the prior constant temperature valve cores are not provided with the function of balanced pressure, which is to say cold and hot water directly enter into a mixed water chamber to mix from the bottom or the side end of the valve core; while the few constant-temperature valve cores that are provided with the function of balanced pressure apply independent balanced pressure assembly to control, whose principle is to balance the inlet water pressure through the floating of the balanced pressure assembly, such as the patent of utility model with authorized publication patent number of CN2874157Y. However, applying independent balanced pressure elements has the disadvantages of complex structure and inconvenient assembly.
Besides, the current constant- temperature valve cores have wider scope of temperature adjusting and higher upper temperature limit, without the control of secure temperature, such accidents as scald, etc. are easier to be caused as the outlet water temperature is too high when operating improperly.